ActionScript 3: Get the percentage of a value within a number range

Sometimes, when creating UI elements or performing geometric calculations based on the sizes or positions of objects (or lots of other tasks), it's useful to find the percentage of a number within a range of 2 other numbers. Use this function to easily relate these values:

/**
 * Returns a percentage of a value in between 2 other numbers.
 * @param bottomRange  low end of the range.
 * @param  topRange  top end of the range.
 * @param  valueInRange value to find a range percentage of.
 * @return The percentage of valueInRange in the range.
 *  @use getPercentWithinRange( 50, 150, 100 );  // displays 50
 */
public static function getPercentWithinRange( bottomRange:Number, topRange:Number, valueInRange:Number ):Number
{
 // normalize values to work off zero
 if( bottomRange < 0 )
 {
  var addToAll:Number = Math.abs( bottomRange );
  bottomRange += addToAll;
  topRange += addToAll;
  valueInRange += addToAll;
 }
 else if( bottomRange > 0 )
 {
  var subFromAll:Number = Math.abs( bottomRange );
  bottomRange -= subFromAll;
  topRange -= subFromAll;
  valueInRange -= subFromAll;
 }
 // simple calc to get percentage 
 return 100 * ( valueInRange / ( topRange - bottomRange ) );
}